This is a note to let you know that I've just added the patch titled
[PATCH 27/28] net: allow pskb_expand_head() to get maximum tailroom
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-allow-pskb_expand_head-to-get-maximum-tailroom.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c29370964ee80c47c09586893b99cc4bfe13295e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Tue, 10 Apr 2012 20:08:39 +0000
Subject: [PATCH 27/28] net: allow pskb_expand_head() to get maximum tailroom
From: Eric Dumazet <[email protected]>
[ Upstream commit 87151b8689d890dfb495081f7be9b9e257f7a2df ]
Marc Merlin reported many order-1 allocations failures in TX path on its
wireless setup, that dont make any sense with MTU=1500 network, and non
SG capable hardware.
Turns out part of the problem comes from pskb_expand_head() not using
ksize() to get exact head size given by kmalloc(). Doing the same thing
than __alloc_skb() allows more tailroom in skb and can prevent future
reallocations.
As a bonus, struct skb_shared_info becomes cache line aligned.
Reported-by: Marc MERLIN <[email protected]>
Tested-by: Marc MERLIN <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/core/skbuff.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -952,9 +952,11 @@ int pskb_expand_head(struct sk_buff *skb
goto adjust_others;
}
- data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
+ data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ gfp_mask);
if (!data)
goto nodata;
+ size = SKB_WITH_OVERHEAD(ksize(data));
/* Copy only real data... and, alas, header. This should be
* optimized for the cases when header is void.
Patches currently in stable-queue which might be from [email protected] are
queue-3.3/net-fix-a-race-in-sock_queue_err_skb.patch
queue-3.3/tcp-allow-splice-to-build-full-tso-packets.patch
queue-3.3/net-fix-proc-net-dev-regression.patch
queue-3.3/tcp-restore-correct-limit.patch
queue-3.3/net-allow-pskb_expand_head-to-get-maximum-tailroom.patch
queue-3.3/net-smsc911x-fix-skb-handling-in-receive-path.patch
queue-3.3/tcp-avoid-order-1-allocations-on-wifi-and-tx-path.patch
queue-3.3/netlink-fix-races-after-skb-queueing.patch
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